Cyclic carbinols



a "co a ne additional ethyl roan:

Patented May 27, 1952 cmmons rGarlsB. Linn,.zllivegslde, 111., assignorto ,Qii-Pmductyfiemny, Chicago, 11]., a corpo- .mthaot no mass Arvlmmn1950' a l- 110. 161,0

combined with m ..msino1' infill);

9 Claims. 1

This invention relates to a new and useful class of alcohols and to aprocess for preparing them.

An object of this invention is to provide a novel class of cyclicalcohols also referred to as cyclic carbinols which are adapted for useas intermediates in organic synthesis, and particuwa im the productionof; of ersanicwan inorganic acids: in the production of haiidesiwbyreplacing the carbinol hydroxyigroupwithhalw in theexid'a-tion-of suchseeondaryeyelic cachlnolstto ketones.

One embodiment c! i this intuition is a carbinci having thestructuralxfnnnula on ,H x

wherein R-represents a -membe-r of thegmup consisting of'-hydrogen anda1k71-srm1pmd "R "remesents'a member oi' the group consisting of sum"group a cycloalkyl group, group. i

oi" invention. relates mwmethri :wearirinci'. hawim: combined with mum;grmipa. cychnentyi ring ."Wiimytm sadnethylwroups.

vza-xnntlmr eialmziin'nent of this; i vest/icon 8 1- Mamba.

- is mund ha desox eswmxmetwnn the formula is a convenient startingmaterialifor the productiun of cyclic yaicohois containing a cyciopentylring in which two adjacent; nuclear carbon atoms with: semina m h lroups. I is ach-o ese djac nuc a n Q La combined wit two meth l ro ps,-

with another nuclear carbonatom their rdacentitB the nueiearcarbomatommun. such .sarhmnls contains-either one or two'methyl groups methyl(pentamethylcyclopentyl) carbinol is obtained by utilizingdesoayrnesityl oxide as a starting material which dehydrated byfractional distillation at a-subatmospheric pressure to form apentamethi'icyciopentenylmethyl ketone which is then, reducedcatalytically with hydrogen to form a carbinol of this invention,namely, 1 (2",2,8-;3,5-' pentamethylcyclopentyl) -ethano1-1. I ment ofthe pentamethylcyclopentenylmethyl istensv is ca r ed 1 exam laa elem? pr i'omabvs tiflit abdnt prei rably. a e tum; o a out :6 (thermal a v..n; hydro enati n; was. .n I lllpo f d '$1 $m .l Q i lyaswm "W. ti tdjin erm e$in nu e. 'piat nnmm s i m lim a 5% 2w ili a on activated'l-riias'cg'iai. and m. cm swa as nclud mm'md m nam u ar i a ofametai'selected e -mm 'w um o swwwand fifin periodic table. thesealumina and alomina-molybd ie oxide 4amticularly effective although-mot*atthe same conditions of operation as utilized with other catalystsmentioned above such as catalysts containing platinam andfor nickel.

Desoxymesityl oxide used as a starting material in this process forproducing the aboveindicated pentamethylcyclopentenylmethyl carbinols isproduced rnesityl oxide with an aluminum-mercury couple in wet ethersolution whereby a condensation occurs which mayhe represented by theiollowing equation;

The resultant di-ketone apparently undergoes an internal'aldolcondensation to give desoxy- Hmesiiyl oxide which is represented by thefore 50 mule:

l/OH

c n o 55 11,0 \C CH.

00 I deaoxmesitvl oxide which is a tertiary-,

?Ihis ;-hydrogenation treat- 3 alcohol loses water readily whenfractionally distilled at reduced pressure and yields an unsaturatedketone which is represented by the structure HgO HI Hi ETOUDS.

As aforementioned, catalytic hydrogenation of the'unsaturated ketoneconverts it into a sat-- which may also be referred to. as l-(2',2',3',3,5'- pentamethylcyclopentyl) -eth'anol-1.

A homolog of this polymethylated cyclopentyl carbinol which containstwomethyl group's combinedflwith the carbinol group is produced byreacting the dehydration product of Ldesoxymesityl oxide withmethylmagnesiumt bromide to form an unsaturated carbinol having twomethyl groups combined with the carbon atom 3 m'lml CHa Otherpolymethylated cyclopentyl carbinols which contain a methyl group andeither in alkyl, cycloalkyl, or arylgroup combined with the car- 4 binolgroup are produced by reacting the dehydration product of desoxymesityloxide with RMgBr in which R represents an alkyl, cycloalkyl, or arylgroup to form an unsaturated carbinol having geminal hydrocarbon groupscom-- bined with the carbon atom of the carbinol group and having adouble bond in the 5-membered ring which is also combined with fivemethyl The resultant pentamethylcyclopentenylmethyl-R-carbinol ishydrogenated catalytically at mild conditions to form a carbinol havingthe formula:

wherein R represents a member of the group consisting of an alkyl group,a cycloalkyl group, and an aryl group.

The nature of the present invention is illustrated further by thefollowing example which should not be misconstrued to limit unduly thegenerally broad scope of the invention.

Mesityl oxide was reduced in wet ether solution by an aluminum-mercurycouple to give a 60% yield of desoxymesityl oxide based upon the amountof mesityl oxide converted. In a typical preparation 200 grams ofaluminum foil was converted into the aluminum-mercury couple followingthe procedure described by Vogel, J. Chem. Soc. 130, 594, (1927). Thisaluminum-mercury couple was then placed in a 5-liter flask provided witha large reflux condenser and containing about 2 liters of ethersaturated with Water. To this mixture in the 5-liter flask, 200 grams ofmesityl oxide was then added. -With an active aluminum-mercury couple,reaction began in a few minutes and reached a maximum in an hour or soand then gradually subsided after which about 100 grams of water wasadded while the vigorous boiling action continued in the reaction flask.After standing overnight, the ether was filtered from the solid whichremained in the flask, was dried over calcium chloride and thendistilled at atmospheric pressure to separate ether from the product,comprising essentially desoxymesityl oxide. A general summary of theproduction of desoxymesityl oxide is given in Table I.

TABLE 1 Reduction of mesityl oxide. with aluminummercury coupleFractional distillation of the desoxymesityl oxide was accompanied byloss of weight at a temperature of about 150 which resulted in theformation of an olefinic ketone (B) which has probably a mixture ofisomers with the oleflnic double bond located at different positions inthe S-membered ring of the pentamethylcyciopentenylmethyl ketone. Aportion of this olefinic ketone (B) was then subjected to catalytichydrogenation in the presence of a nickel-diatomaceous earth catalystcontaining about 60% by weight of freshly reduced nickel. The resultsobtained in these hydrogenations runs at temperatures of 25 and 75 C.are

indicated in Table 11.

TABLE II Runs 1 2 Vol. Bomb. mi 128 450 Grams (B) charged 10 37n-Pentane m 220 03 Gram Ni catalyst l 5 Initial Hydrogen Pressure, Atrn100 100 Temperature, C 25 75 Hours A". 14 4 Hydrogen absorbed, Mols, permol (B) 2.0 2. 2

DISTILLATION F PRODUCT FROM RUN 1 Cut B. PM o. gfi g 1m DISTILLATION 0FPRODUCT FROM HUN 2 B. 1 35M. K 0 51 12 ELEMENTARY ANALYSIS Found forCalc. for Run 1, Run 2, 0113140 Cut 2 Cut 3 Percent C -4 78. 50 78. 6878. 19 Percent H 12. 74 13.13 13.13

Infrared analysis of the resultant hydrogenated product boiling between215 and 220 C. at 760 mm. pressure showed it to contain an hydroxylgroup and in general to be in agreement with values expected for acarbinol with the structure HaC- CH| Accordingly, at low temperaturescatalytic hydrogenation of the unsaturated dehydrogenation product ofdesoxymesityl oxide saturated the double bond and also reduces thecarbinol group to an hydroxyl group, giving a carbinol with thestructure shown above.

I claim as my invention:

1. A carbinol having the structural formula CH: H

wherein R represents a member of the group consisting of hydrogen and analkyl group and R represents a member of the group consisting of analkyl group, a cycloalkyl group, and an aryl group.

2. A carbinol as defined in claim 1 further characterized in that Rrepresents an alkyl group.

3. A methyl carbinol having combined with the carbinol group acyclopentyl ring with two adjacent nuclear carbon atoms combined withgeminal methyl groups.

4. A methyl carbinol as defined in claim 3 further characterized in thatsaid cyclopentyl ring has a methyl substituent at the 5-position and isunsubstituted at the 4-position.

5. 1- (2',2',3,3',5'-pentamethylcyclopentyl) -ethanol-l.

6. 2- (2',2',3',3, '-pentamethylcyclopentyl)-propanol-2.

'7. A process for producing1-(2,2',3',3,5'-pentamethylcyclopentyl)-ethanol-1 which compriseshydrogenating 2',2',3',3',5' pentamethylcyclopentenylmethyl ketone at atemperature or from about 10 to about C. in the presence 01' ahydrogenation catalyst to form l-(2',2,3',3',5'- pentamethylcyclopentyl)-ethanol-1.

8. A process which comprises hydrogenating 2',2',3,3',5-pentamethylcyclopentenylmethyl ke tone in the presence of a nickelcatalyst at a temperature of from about 10 to about 75 C. and recoveringthe resultant 1-(2',2',3',3,5'-pentamethylcyclopentyl) -ethanol-1.

9. A carbinol having at least two carbon atoms in its carbinol group andhaving attached to one of said carbon atoms a2,2',3,3,5'-pentamethylcyclopentenyl group.

CARL B. LINN.

REFERENCES CITED The following references are of record in the file ofthis patent:

- UNITED STATES PATENTS Number Name Date 2,435,403 Morris et a1 Feb. 3,1948

1. A CARBINOL HAVING THE STRUCTURAL FORMULA